The Port of Houston is a port in Houston, Texas, the fourth-largest city in the United States. The port is a 25-mile-long complex of diversified public and private facilities located a few hours' sailing time from the Gulf of Mexico. It is the busiest port in the United States in terms of foreign tonnage, second-busiest in the United States in terms of overall tonnage, and thirteenth-busiest in the world. Though originally the port's terminals were primarily within the Houston city limits, the port has expanded to such a degree that today it has facilities in multiple communities in the surrounding area.